Learning CSS

Currently I'm learning CSS in order to modify Gradient iCool for the application of FF3. Feel free to state the problems encountered in FF3 when using the theme.
Known Issues are:
#1 Search Bar
#2 Tab
#3 Close buttons
#4 Buttons in Add-ons and Options
I'll try my best to improve this theme as soon as possible. If you could provide any comment or help in the script, I would be thankful.
Also, congratulations to Gradient iCool, which is about to reach a total download of 2,000. Hope more and more people will download this theme.
I'll upload the previews here as soon as possible. Thanks a lot.

Grdient Themes

I've changed Ozone Themes to Gradient Themes. The first theme out is Gradient iCool (Fig.1), which is the successor of Ozone Black x Blue. First, I greatly appreciate those who has downloaded this theme. Now it has reached over 700 downloads for a week hosted (i.e. 100 downloads per day!)
Just tell me anything you feel about this theme here. Feel free also to post comments on the Mozilla Addons page.

Fig. 1